On a warm afternoon in late July I'm in Bushy park watching a small flock of swifts twisting and turning over the playing field.

Suddenly a lone swallow speeds through them in an unwavering straight line skimming the grass and disappears into the distance.

That was the last time I saw swifts in any numbers as they are now beginning their epic flight south after their short three month stay with us and will sadly have all gone by about the 8th august.

Some way above, two buzzards circle lazily with scarcely a wing beat, riding the thermals, soaring higher and higher until almost lost to view (pictured) in the hazy blue.

The Bushy buzzards could be the same duo increasingly being seen over south west London locations as they are very free ranging birds.

When I was a boy, the only time I could see buzzards was when on holiday in wildest Wales, but since then buzzards have spread throughout England in common with red kites and peregrine falcons in what amounts to a phenomenal success story for each species.

This is in complete contrast to many birds including skylarks, swifts sing thrushes and cuckoos, all of which have declined markedly in the past thirty years.

So, swifts arrived earlier than usual in the glorious weather of April and May and seem to be leaving earlier too, probably and hopefully as a result of a successful breeding season.